This disclosure relates generally to a turbomachine shroud and, more particularly, to distributing stress in an annular turbomachine shroud.
Turbomachines extract energy from a flow of fluid as is known. During operation, air is pulled into the turbomachine. The air is then compressed and combusted. The products of combustion expand to rotatably drive a turbine section of the turbomachine. As known, shrouds (or blade outer air seals) seal against rotating components of the turbomachines. Sealing interfaces between the rotating components and the shrouds increases engine efficiencies.
One example turbomachine is an auxiliary power unit (APU). APUs are typically located in the tail sections of large aircraft. The APUs provides electrical power and compressed air to the aircraft. APUs, and other turbomachines, experience extreme temperatures during operation. Shrouds in the APUs, which are typically annular and formed of a single piece, must accommodate these temperatures to maintain sealing interfaces with other components.
Shrouds made from ceramic materials particularly silicon-based ceramics such as silicon carbide (SiC) and silicon nitride (Si3N4) offer unique benefits by enabling tighter tip clearances and therefore improved efficiency. Additionally ceramic materials are refractory and allow for the design of highly efficient turbomachines. However, ceramic materials are brittle and need to be designed with specific considerations to mitigate the risks associated with flaw sensitivity of the material.